-LRB- CNN -RRB- -- One of al Qaeda 's most influential figures in North Africa has been killed by French and Chadian forces , a U.S. official said Friday .

French military sources had earlier said that Abdelhamid Abou Zeid , a deputy leader of al Qaeda in the Islamic Maghreb , was killed in an airstrike in Mali late last month .

Abou Zeid was one of the group 's most ruthless commanders , having seized at least a dozen foreigners for ransom . At least two have been killed ; several French citizens remain captive .

`` He was a senior influential member of AQIM , and his death represents a significant blow to AQIM 's efforts to use West Africa , and Mali in particular , as a safe haven , '' the official told CNN .

Military sources quoted by French media say that in the past few days , Abou Zeid and a substantial number of his fighters were killed during a French bombardment near Aguelhok in northern Mali .

His death was first reported by an Algerian television station Ennahar .

A spokesman for the French Defense Ministry refused to comment on the reports .

The ministry did say air force operations are continuing , including in the Tessalit region , where close to 100 air sorties were carried out this week .

Aguelhok is a remote town close to mountains and the Algerian border -- in a region where many Islamist fighters had regrouped in the face of the French push toward the main cities of the north .

According to analysts , it is an area that Abou Zeid was intimately familiar with , as for years it was his main base of operations before Islamists took over much of northern Mali .

For much of the last year , a constellation of jihadist forces including Abou Zeid had controlled large parts of northern Mali after ethnic Tuareg rebels had forced the army to retreat . He spent much of his time in and around Timbuktu , partly at a luxurious mansion that had been built for Moammar Gadhafi , according to reports from the city .

At the beginning of this year , Abou Zeid joined other Islamist forces making a push southward toward the capital , Bamako . But when the Islamist advances prompted a French intervention , he moved to the area around the less accessible city of Kidal , close to the virtually impenetrable Ifoghas Mountains .

Abou Zeid had been promoted by the emir of AQIM -- and fellow Algerian -- Abdelmalek Droukdel . Droukdel saw him as a loyal counter to the growing power of a rival jihadist commander , Moktar Belmoktar , the man who ordered the hostage attack on the Algerian gas plant in January .

Abou Zeid 's ruthlessness -- and his growing influence -- were confirmed three years ago when he ordered the beheading of an elderly British tourist -- Edwin Dyer -- who 'd been seized by his group early in 2009 . When Malian authorities rounded up a number of al Qaeda suspects in response , Abou Zeid sent a hit squad to the Timbuktu home of a senior intelligence officer , who was shot dead .

The following year , a French aid worker , 78-year old Michel Germaneau , was killed as French commandos tried to rescue him . Abou Zeid 's group also staged a raid on a uranium mine in neighboring Niger -- abducting seven workers , four of whom , all French , are still being held .

One of the few Westerners to have encountered Abou Zeid was a French citizen , Pierre Camatte , who was abducted from a hotel in northern Mali in November 2009 .

`` Physically , there is nothing remarkable about Abou Zeid , '' he told Le Monde 's Isabelle Mandraud after his release . `` He is small , and thin . But he seems to be highly respected by members of his entourage . ''

`` He wanted to know whether I knew of any mapping websites on the Internet , Russian websites , so that he could have real-time images . ''

Abou Zeid 's hostage-taking provoked a trial of strength with Belmoktar , who had generated significant funds for jihad from ransom payments for foreign hostages .

By all accounts , the two were very different characters . Abou Zeid had a reputation for extreme brutality and thuggishness , while Belmoktar developed a reputation for strategic cunning . Analysts tell CNN that despite their rivarly , the two men found ways to coexist .

The fall of Gadhafi in Libya gave both men the opportunity to take their operations northward into Libya from their sub-Saharan strongholds . Sources briefed by Western intelligence told CNN that Belmoktar and Abou Zeid made trips to Libya to explore the possibility of cooperation with local Libyan jihadist groups , secure weapons supplies and scout out possible locations for training facilities .

Abou Zeid made several trips to Libya in 2011 , according to one source familiar with intelligence from the area .

He was one of several al Qaeda figures in North Africa who had fought in Algeria 's vicious insurgency in the 1990s , when whole villages were massacred and atrocities were committed by both Islamist militants and Algeria 's counterterrorism forces .

As a child growing up in a poor region of southern Algeria , Abou Zeid had little formal schooling , but his intimate knowledge of the border with Libya made him an expert smuggler .

According to Dario Cristiani , writing in the Jamestown Foundation 's Militant Leadership Monitor , he was radicalized by several run-ins with the Algerian authorities . And he was at the heart of the transformation of the Algerian insurgency into an al Qaeda affiliate .

Abou Zeid 's death casts further uncertainty over the fate of the French hostages his group is still believed to hold .

In December , before the French intervention in Mali , he accused the French authorities of blocking negotiations for their safe release . Several of the hostages had appeared in videos warning against military intervention for the sake of their own safety . In one video , with masked men holding AK-47s behind them , the men look exhausted and terrified .

Andrew Lebovich , a Senegal-based analyst who recently traveled to Mali , told CNN there is concern that Abou Zeid transported a number of Western hostages with him after he left Timbuktu .

If Abou Zeid was indeed killed , the expectation is his group will retaliate .

`` According to available accounts , he was somebody who generated fierce respect and loyalty in his men , so unless his fighting force has been severely degraded , there 's a chance his group may lash out to avenge his death in the days and weeks ahead , '' Lebovich said .

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NEW : U.S. official confirms death of Abdelhamid Abou Zeid

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The al Qaeda figure was killed in French airstrike , French military sources have said

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The deputy leader of al Qaeda in the Islamic Maghreb and his fighters were in northern Mali

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He had a reputation for brutality